Abstract: A device with an adjustment bolt includes a bolt attachment wall, an adjustment bolt screwed with an internal thread hole of the bolt attachment wall, a locknut screwed with the adjustment bolt, a cover that surrounds the adjustment bolt and the locknut, and a stopper unit that prevents removal of the cover from the locknut. The stopper unit includes an inner circumference groove of the cover fitted around a C-shaped retaining ring, and an external circumference groove of the locknut fitting within the retaining ring. The external circumference groove includes a first groove portion having a large-diameter groove bottom that restricts contraction and removal of the retaining ring fitted within the inner circumference groove, and a second groove portion provided continuously for the first groove portion and having a small-diameter groove bottom that allows contraction and removal of the retaining ring fitted within the inner circumference groove.

Abstract: A device with an adjustment bolt includes a bolt attachment wall, an adjustment bolt screwed with an internal thread hole of the bolt attachment wall, a locknut screwed with the adjustment bolt, a cover that surrounds the adjustment bolt and the locknut, and a stopper unit that prevents removal of the cover from the locknut. The stopper unit includes an inner circumference groove of the cover fitted around a C-shaped retaining ring, and an external circumference groove of the locknut fitting within the retaining ring. The external circumference groove includes a first groove portion having a large-diameter groove bottom that restricts contraction and removal of the retaining ring fitted within the inner circumference groove, and a second groove portion provided continuously for the first groove portion and having a small-diameter groove bottom that allows contraction and removal of the retaining ring fitted within the inner circumference groove.

Abstract: In a plughole waterproofing device for an engine, a coil case is fitted onto the ignition coil that is accommodated in a plughole of an engine, and an upper portion of the case protruding above the engine is provided with a longitudinal air path extending upward from a lower end thereof communicating with the plughole and a vent hole communicating with an upper end portion of the air path and opened to ambient air. A cover wall hanging while surrounding the vent hole is continuously provided on the case upper portion, and an air chamber is formed inside the cover wall, the vent hole being opened in an upper portion of the air chamber, and an opening face being formed at an entire bottom of the air chamber opening toward the engine.

Abstract: An oil-release space (18) is formed along a lower side portion (17) of a cylinder lateral and peripheral wall (3) below an oil-cooling jacket (4). A reinforcing plate (19) spans between the lower side portion (17) of the cylinder lateral and peripheral wall (3) and a bottom wall (10) of a push-rod chamber (8) below the oil-release space (18). The oil-release space (18) is communicated with an oil outlet (20) of an oil-return passage (7). Engine oil that has passed through the oil-return passage (7) is released from the oil outlet (20) into the oil-release space (18). The engine oil released into the oil-release space (18) is guided by an upper surface of the reinforcing plate (19) to drop from a led-out end (25) on a rear side of the reinforcing plate (19) onto a rear side space (24).

Abstract: In a plughole waterproofing device for an engine, a coil case for covering an ignition coil is fitted onto the ignition coil that is accommodated, together with an ignition plug, in a plughole opened to an upper surface of an engine, and a longitudinal air path extending upward from a lower end portion of the case upper portion communicating with the plughole and a vent hole communicating with an upper end portion of the longitudinal air path and being opened to ambient air are provided in a case upper portion, protruding above the engine, of the coil case. The vent hole is provided in an upper portion of the case upper portion. A cover wall hanging while surrounding the vent hole is continuously provided on the case upper portion, and an air chamber is formed inside the cover wall, the vent hole being opened in an upper portion of the air chamber, an opening face being formed at an entire bottom of the air chamber in such a manner as to open toward the engine.

Abstract: An oil-release space (18) is formed along a lower side portion (17) of a cylinder lateral and peripheral wall (3) below an oil-cooling jacket (4). A reinforcing plate (19) spans between the lower side portion (17) of the cylinder lateral and peripheral wall (3) and a bottom wall (10) of a push-rod chamber (8) below the oil-release space (18). The oil-release space (18) is communicated with an oil outlet (20) of an oil-return passage (7). Engine oil that has passed through the oil-return passage (7) is released from the oil outlet (20) into the oil-release space (18). The engine oil released into the oil-release space (18) is guided by an upper surface of the reinforcing plate (19) to drop from a led-out end (25) on a rear side of the reinforcing plate (19) onto a rear side space (24).

Abstract: Cap segment surfaces (9a) and (9b) of a larger-diameter end portion (7) of a connecting rod (5) are positioned at an upper and a lower portions of a crank pin (8) and are inclined from a right upper portion of the larger-diameter end portion (7) of the connecting rod (5) to a left lower portion thereof. A cap (10) is attached by connecting rod bolts (11a) and (11b), head portion (12a) and (12b) of which are arranged vertically along the inclination direction of the cap segment surfaces (9a) and (9b). With a piston (24) existing at a bottom dead center, a weight connection portion (15a) of an upper rotary balancer (4a) is provided with a recess (13a) at a portion oriented leftwards and downwards which comes to face the head portion (12a) of the upper connecting rod bolt (11a).

Abstract: In an inclined engine where a cylinder (2) projects from a crank case (1) obliquely and upwardly, when seen in a direction parallel to a center axis (3) of a crank shaft (10), under a specific observation condition in which the cylinder projecting direction is deemed as an upper right side, a valve operating cam gear (5) meshes with a crank gear (4) from a horizontal right side of the latter and a governor gear (6) is arranged in a space defined below a portion where the valve operating cam gear (5) meshes with the crank gear (4). This governor gear (6) engages with the valve operating cam gear (5) from a lower left side of the latter.

Abstract: The centrifugal governor ensures that the governor lever (3) can apply a synthesized tensile force (STF) of the tensile forces (GS) of the main spring (4) and the tensile force (IS) of the idling spring (5) to the fuel adjuster (2) of the fuel pump (1) so as to increase the supply of fuel, and cause the governor weight (6) to decrease the fuel amount by pushing down the fuel adjuster (2), so that a disequilibrium between the synthetic tensile force (STF) of the two springs (4), (5) and the governor force (GF) is utilized for increasing or decreasing the supply of fuel through the operation of the fuel adjuster (2), and that the idling spring (5) which is constituted as a tension coiled spring spring-biases the governor lever (3) in the direction of increasing the supply of the fuel both in the non-load set and in the low-load set (LL), and negates the spring-biasing both in the high-load set (LH) and in the full-load set (4/4).

Abstract: Cap segment surfaces (9a) and (9b) of a larger-diameter end portion (7) of a connecting rod (5) are positioned at an upper and a lower portions of a crank pin (8) and are inclined from a right upper portion of the larger-diameter end portion (7) of the connecting rod (5) to a left lower portion thereof. A cap (10) is attached by connecting rod bolts (11a) and (11b), head portion (12a) and (12b) of which are arranged vertically along the inclination direction of the cap segment surfaces (9a) and (9b). With a piston (24) existing at a bottom dead center, a weight connection portion (15a) of an upper rotary balancer (4a) is provided with a recess (13a) at a portion oriented leftwards and downwards which comes to face the head portion (12a) of the upper connecting rod bolt (11a).

Abstract: The centrifugal governor ensures that the governor lever (3) can apply a synthesized tensile force (STF) of the tensile forces (GS) of the main spring (4) and the tensile force (IS) of the idling spring (5) to the fuel adjuster (2) of the fuel pump (1) so as to increase the supply of fuel, and cause the governor weight (6) to decrease the fuel amount by pushing down the fuel adjuster (2), so that a disequilibrium between the synthetic tensile force (STF) of the two springs (4), (5) and the governor force (GF) is utilized for increasing or decreasing the supply of fuel through the operation of the fuel adjuster (2), and that the idling spring (5) which is constituted as a tension coiled spring spring-biases the governor lever (3) in the direction of increasing the supply of the fuel both in the non-load set and in the low-load set (LL), and negates the spring-biasing both in the high-load set (LH) and in the full-load set (4/4).

Abstract: In an inclined engine where a cylinder (2) projects from a crank case (1) obliquely and upwardly, when seen in a direction parallel to a center axis (3) of a crank shaft (10), under a specific observation condition in which the cylinder projecting direction is deemed as an upper right side, a valve operating cam gear (5) meshes with a crank gear (4) from a horizontal right side of the latter and a governor gear (6) is arranged in a space defined below a portion where the valve operating cam gear (5) meshes with the crank gear (4). This governor gear (6) engages with the valve operating cam gear (5) from a lower left side of the latter.